High resolution solid state image sensors such as charge-coupled devices (CCD), charge-injection-detectors (CID), and so forth, are finding increasing use as imaging elements for cameras. Such high resolution image sensors produce a large number of pixels for each horizontal scan line of their output, for example, 1146 pixels.
A conventional low resolution TV video signal allows only 53.5 .mu.'s for encoding the information contained in each horizontal line of output. Thus, if 1146 pixels from the above signal is encoded in the time provided by the low resolution video format, a bandwidth equal to (1146/2)/53.2 .mu.'s or approximately 10.75 MHz is required. Such a bandwidth far exceeds the capability of a conventional video-cassette-recorder (VCR) tape used for video tape recording, since the luminance bandwidth of such recorders is limited to approximately 2 MHz. As a result, any CCD camera having more than 200 horizontal pixels in a continuous horizontal readout will exceed the recording capability of most conventional VCR's.
At present, in transferring the output of a high resolution sensor to a conventional VCR tape, a large percentage of the image sensor output signal is typically lost as a result of the signal being constrained by the bandwidth limitations of the VCR and, as a consequence, a substantial amount of resolution is lost.
The above-described situation limits the use of VCR recorders for taking high resolution still pictures. However, as described above, the limitation occurs as a result of the limitations inherent to the conventional VCR.
Therefore, it is a primary object of this invention to provide an apparatus for converting a high resolution still image sensor output signal to a format which is compatible for storage in a conventional VCR and which can be distinguished from a low resolution video output signal.
It is a further object of this invention to provide a method and apparatus for interspersing conventional TV video signals with high resolution still image signals on the same video tape thereby permitting the use of a high resolution camera to video tape scenes for replay on a typical CRT monitor and to intersperse the low resolution video images with high resolution still images which can be detected and displayed on the same monitor.
Other objects of the invention will be, in part, obvious and will, in part, appear hereinafter. The invention accordingly comprises a system possessing the construction, combination of elements and arrangement of parts which are exemplified in the following detailed disclosure.